I have accumulated a plethora of 12As. I have 4 assembled motors and 1 disassembled that I believe I have all the pieces for. All are from First Gen RX7s. 1 ran in the MG before it sprung a water leak, 1 is supposably rebuilt but not ran, 2 are unknown conditions. So all are "Cores". I have no idea what these are worth now. I looked at Ebay completed listings and the values of core engines are not really believable but I know parts have dried up for these. If I'm honest there is 0 chance I will use them ever so it's time to send them down the road. RX7Club doesn't seem to have a lot of people in the 12A market. I don't want to get rich off them but also don't want to give them away.
So what's a good value? Anyone interested in 5 12As?
I've got a 1983 GSL with an original, 50K mile engine that runs perfectly.
Too bad you're in Illinois as I'd buy at least one if you were local (California) just so I'd have options.
My car is an automatic and I'd really like to convert it to manual so I'm more on the hunt for transmissions. Realistically though, I won't have time until I retire in a couple of years and it's a super clean, matching number car so at some point, I may actually hurt it's value by doing the conversion.
Please keep us informed on this.
Added later...
I do want an original alternator as I didn't think to have the core rebuilt so now my engine compartment isn't bone stock.
I see you're looking to bundle all the engines into one sale so I doubt you want to fool around with selling one alternator and I'd be looking for a clean, corrosion free unit to match everything else but I thought I'd let you know just in case you're interested.
Hmm. Given that I have a car that's running a 12A of indeterminate mileage, I might be interested in one or two.
I could be interested in one as well.
How much would you find reasonable to pay for such spinning magic triangles?
Where was this four years ago? 
The last core I sold a few years back was $300 if i recall correctly. From what i see it really depends on the internal conditon. Especially the chrome flaking on the housings.
For a quicker sale I would say bundling them I would think maybe $1500 for all 5 or list them for $500 each and they would probably be gone pretty quick. I am not really looking but would be interested around that price point if I saw an add like that.
Getting some compression numbers you very well may be able to pull $750 or more if they come back testing well.
Here's a parts lot that popped up in central VA for reference.
https://richmond.craigslist.org/pts/d/henrico-mazda-rx7-12a-parts/7419554652.html
Mazda Rx7 12a parts - $500 (Short pump)
condition: good
make / manufacturer: Mazda
model name / number: Rx7
Complete, disassembled, engine plus additional parts. Housings, irons, intake, carb, exhaus manifold, water pump, oil pan, etc. everything to assemble a complete engine. Housing have some chrome chipping, but they’re usable. I think I have 5 housings… on is mint, but has been modified for a bridge port. I have about 1.75 engines worth of 12a parts I want to get rid of. No parting out. You have to take everything. $500.
